The present invention relates to a system for providing an electrostatic charge on liquids to be applied to other objects utilizing equipment that is simple to manufacture and use and is electrically isolated from low voltage supports in a manner to reduce the leakage of current to ground.
Various electrostatic spray systems have been advanced for spraying materials. U.S. Pat. No. 4,788,617 discloses an electrostatic spray system which utilizes two containers, with liquid transfer between the containers. An electrostatic charge is applied to a liquid in one container and the liquid is then sprayed onto plants, for example. This device requires two closed tanks that are pressurized and requires control over the current flow between the tanks for operation.
Another arrangement for applying coating materials utilizing an electrostatic spray system is shown in U.S. Pat. No. 3,934,055. An enclosed tank is provided for sprinkling a coating supply, and the unit is then passed across a high voltage electrode on the interior of a hose which carries liquid to a spray gun. An enclosed system is disclosed, with venting to atmosphere and with the use of a grounded outer housing.
It has been discovered that using an open-top container, and controlling the spacing between a head sprinkling liquid into the container and then providing an electrostatic charge to the liquid as it is pumped from the container provides a simplified construction since the container, the pump and other parts are isolated from ground through suitable insulators.